Dynamic and static stability testing was performed on a tongue-in-groove joint using air as the driving fluid. The testing was performed to evaluate the conditions that would produce oscillations that could result in sustained vibration of the test piece (dynamic instability) and to determine the conditions for which the joint would seal (static instability). The key variables that were adjusted in the test were the length of the gap, the width of the gap, and the position of the tongue within the groove. Four test configurations were evaluated with different gap widths and engagement lengths to produce L/go (tongue engagement length to groove gap width) ratios ranging from 1.2 to 42. The smallest L/go configuration, which was the most dynamically unstable configuration, was repeated with damping added to the spring-mass system. Each configuration was flow tested over a range of differential pressures and disk positions within the groove. Differential pressure, disk position, displacement due to disk vibration, disk acceleration, flow through the gap, and acoustic pressure in the gap were measured and recorded. Testing showed the most violent unstable behavior occurs when the disk is centered in the groove, while the behavior tends to be stable when the disk is near the downstream sealing surface of the groove.

This content is only available via PDF.
You do not currently have access to this content.